The present invention relates generally to an apparatus and method for making simulated felled or lap seams, and more particularly to the apparatus for folding the material to form such simulated felled or lap seam.
In the garment industry, as well as in other fabric sewing operations, it is quite often customary to join adjacent overlapped edges of two fabric members in what is referred to as a "felled," "felled," or "lap" seam. An example of such seams is best illustrated by reference to the side seams in the legs of jeans. The terms "felled," "felled," or "lap" seams is understood to refer to seams in which proximate marginal portions of adjacent fabric members are first overlapped, then the upper one of the fabric members is folded around the edge of the lower fabric member to underlie the overlapped margins and the lower of the fabric members is folded around the edge of the upper fabric member to overlie the overlapped margins. This results in a four-ply seam which is subsequently seamed by zig-zag stitches or, more conventionally, by a pair of parallel longitudinal row of stitches.
Various apparatuses have been developed for processing overlapped fabric members through a folding station to prepare the felled seam for the stitching operation. Examples of such apparatuses are illustrated in U.S. Pat. Nos. 2,096,330 to Le Vesconte and 4,476,792 to Diacont, have become conventional in the sewing industry. While such seams result in an extremely strong fabric joint, several attendant problems have appeared. For example, the four-ply construction obviously requires additional material to form the two overlapping proximate marginal portions. This additional material is both costly and makes the garment seams more bulky than necessary. Such bulky seams tend to ripple when washed.
A preferable type of seam to use as a replacement for conventional felled seams is the "simulated felled seam" in which the proximate margins of two adjacent fabric members are abutted, rather than overlapped, preliminarily united by a row of basting stitches and then folded into a three-ply construction. In this approach, after the preliminary butt seam is formed, one of the fabric members is folded along an imaginary line on one side of the row of basting stitches to underline the united margins and the other of the fabric members is reverse folded along an imaginary line on the other side of the row of basting stitches to overlie the united margins. An example of this type of seam is illustrated and described in U.S. Pat. No. 2,169,590 to Myers (see FIGS. 3, 4, and 7). Such construction eliminates one of the plies which both saves material and thus expense, and looks better. Further, there is no apparent loss of strength in such a seam. One drawback to date of such a type of seam is that there is no automated equipment for forming such a seam. It is believed that one reason why no such equipment is presently available is perhaps twofold. The first reason is because of the problem attendant to maintaining the preliminary butt seam formed by the abutting edges of the two fabric members consistently in the center of the resulting folded seam. Secondly, it is difficult to keep an accurate, small amount of turn-under in a folder.
It is this problem which has been confronted and solved in the present invention. In general then, the present invention is directed to an apparatus and method for forming such simulated felled seams automatically and in such a manner as to maintain the abutting edges of the two fabric members centrally located between the parallel row of finish stitches of the resulting finished seam. In the approach of the present invention, there is provided a preliminary basting station which receives a pair of aligned and abutting fabric members and preliminarily joins them together, preferably by applying a uniting row of basting stitches therebetween. Alternatively the basting seam might be formed by gluing or with other conventional joining means. The preliminarily joined pair of fabric members is then presented to a unique folding station which folds one fabric member beneath the united margins and folds the other fabric member to overlie the united margins as the fabric members are fed along the folding station. Subsequently, a final seaming station, preferably in the form of a multiple needle sewing machine, applies two or more rows of stitches longitudinally of the folded seam.
The folding apparatus may be an integral part of a machine incorporating both zig-zag and multiple needle heads axially aligned with one another. Alternatively, the folder may be provided with its own table as an independent piece of apparatus which is interposed in alignment between the sewing tables of the zig-zag and multiple needle machine. For for further versatility, material may be fed through a zig-zag machine (or other means of joining) at one station to provide the preliminarily basted seam which, at a later time, can be fed through the novel folding apparatus and a multiple needle machine at another sewing station to make the final lap seams.
The folding apparatus itself lies at the heart of the invention and includes a base plate having a guide rib or scroll extending generally upwardly therefrom and a generally horizontal guide plate spaced above the surface of the base plate a distance at least as great as the thickness of one of the fabric members. The guide plate includes a longitudinal edge which extends substantially the entire length of the base plate along a feed path substantially parallel with a line formed by the abutting edges of the fabric members, and forms the aforesaid line around which the underlying fabric member is folded. The guide rib or scroll is positioned adjacent the longitudinal edge of the guide plate and includes a first upstanding curved edge that is so constructed as to lift the united margins and the eventual overlying fabric member up and around the longitudinal edge of the guide plate while holding the eventual underlying fabric member therebeneath. A second upstanding curved edge downstream of the first curved edge forms the line about which the overlying fabric member is reverse folded to overlie the united margins.
It is therefore an object of the present invention to provide an apparatus and technique for forming simulated felled seams in an automatic, continuous operation.
It is another object of the present invention to provide an apparatus and technique for forming seams of the type described in which the preliminary butt seam formed by the abutting edges of the two fabric members is maintained centrally within the confines of the resulting felled seam.
A further object of the present invention is to provide an apparatus and technique of the type described in which the preliminary butt seam formed by the abutting edges of the adjacent fabric members is positively engaged by a guide edge throughout the majority of the folding operation to ensure that it is maintained centrally between the confines of the eventual felled seam.